I don't know off the top of my head. But whenever shopping around for Windows laptops I always consult the objective battery life tests done by notebookcheck.net
For example, according to these reviews, the battery life (for wifi surfing test) on the QHD version of Dell XPS 13 is as good as the retina MBP when power saving mode is on
http://www.notebookcheck.net/Dell-XPS-13-9343-Touchscreen-Ultrabook-Review.135817.0.html
http://www.notebookcheck.net/Apple-MacBook-Pro-Retina-13-Early-2015-Notebook-Review.139621.0.html
One note on very high res displays in Windows. I've always shied away from going above FHD because my understanding is there are a lot of desktop class Windows applications that don't scale well on very high res displays. But perhaps someone can say if this situation is improving?
Some issues I have encountered with this in the past (although its around 3 years since I last used bootcamp):
- You don't get the full set of security features in Windows - e.g. Bitlocker disk encryption
- Many disk imaging based backup software for Windows won't work.
- You take a hit on battery life
- Not all Windows trackpad gestures work
- Can be non-optimal to use a Mac keyboard in Windows